Loss of Lean Body Mass as an Independent Risk Factor for Continuation of S-1 Adjuvant Chemotherapy for Gastric Cancer

Compliance with S-1 adjuvant chemotherapy is not satisfactory, and the aim of the present study was to clarify risk factors for the continuation of S-1 after gastrectomy. This retrospective study selected patients who underwent curative D2 surgery for gastric cancer, were diagnosed with stage II/III disease, had a creatinine clearance > 60 ml/min, and received adjuvant S-1 at our institution between June 2010 and March 2014. The time to S-1 treatment failure (TTF) was calculated. Fifty-eight patients were selected for the present study. When the TTF curves stratified by each clinical factor were compared using the log-rank test, lean body-mass loss (LBL) of 5 % was regarded as a critical cutoff point. Univariate Cox's proportional hazard analyses demonstrated that LBL was a significant independent risk factor for continuation. The 6-month continuation rate was 91.7 % in patients with an LBL < 5 %, and 66.3 % for patients with an LBL > 5 % (p = 0.031). The present study demonstrated that LBL might be an important risk factor for a decrease in compliance to adjuvant chemotherapy with S-1 in patients with stage II/III gastric cancer who underwent D2 gastrectomy. A multicenter, double-blinded, prospective cohort study is necessary to confirm whether LBL would affect adjuvant S-1 continuation.